Some hauntings feature a single phenomenon - such as a particular door slamming shut that occurs repeatedly - while others consist of many different phenomena, ranging from odd noises to full-blown apparitions.
Here's a partial list of phenomena that might indicate that your house is haunted:

Unexplained noises:
footsteps; knocks, banging, rapping; scratching sounds; sounds of something being dropped.

Doors, cabinets/cupboards opening/closing:
most often, these phenomena are not seen directly. You either hear the distinct sounds of the doors opening and closing or return to a room to find a door open or closed. Sometimes furniture, like kitchen chairs have been moved.

Lights turning off and on:
likewise, these events are seldom seen actually occurring, but the lights are switched on or off when you know they were not left that way. This can also happen with TVs, radios and other electrically powered items.

Items disappearing and reappearing:
it's the familiar experience of not being able to find a regularly used item - say, your keys - which you believe you placed in a spot you always place them. Some time later, the keys are found - in exactly the place you normally put them.

Unexplained shadows:
the sighting of fleeting shapes and shadows, usually seen out of the corner of the eye.  Many times, the shadows have vaguely human forms, while other times they are less distinguishable or smaller.

Strange animal behavior:
a dog, cat or other pet behaves strangely. Dogs may bark at something unseen, cower without apparent reason or refuse to enter a room they normally do. Cats may seem to be "watching" something cross a room. Animals have sharper senses than humans,

Feelings of being watched:
this is not an uncommon feeling and can be attributed to many things, but it could have a paranormal source if the feeling consistently occurs in a particular part of the house at a particul

Psychokinetic phenomena:
hearing a door open or close is one thing. Actually seeing it happen is quite another. Doors and windows are locked or unlocked. Some people also report that when they are in bed they can feel and/or hear something sitting on the bed.

Feelings of being touched:
the feeling of being watched is one thing, and actually feeling like you are being touched is quite another. Some people feel something brush past them, something touching their hair or "a hand" on the shoulder. Some feel a gentle poke, push or nudge.

Cries and whispers:
on occasion, muffled voices, whispering and crying can be heard. Sometimes it's music from some unknown source. People hear their names being said.

Cold or hot spots:
cold spots are classic haunting symptoms,

Unexplained smells:
the distinct fragrance of a perfume or cologne that you do not have in your house. This phenomenon comes and goes without any apparent cause.

Moving or levitating objects (severe psychokinetic phenomena):
dinner plates sliding across the table; pictures flying off walls; doors slamming shut with great force; furniture sliding across the floor.

Physical assault:
scratches, slaps and hard shoves. This kind of personal assault is extremely rare, but obviously highly disturbing.

Other physical evidence:
unexplained writing on paper or walls; handprints and footprints.

Apparitions:
physical manifestation of a spirit or entity.

So, if you have some of this signs in your home, you should probably call the winchesters:)